Forbes pleaded guilty and was given an automatic life sentence for killing 19-year-old Kenia Monge. Denver Police say they arrested Kerry Humphrey on Oct. 5.

Lynn Kimbrough, a spokeswoman for the Denver District Attorney's office, says Humphrey was arrested for investigation of one felony count of attempt to influence a public servant.

The DA says formal charges are expected to be filed by next week.

9NEWS did a criminal background check and found no prior record for Humphrey. If convicted, Humphrey could spend six years in prison.

No more details in this case are available because the arrest affidavit has been sealed.

Humphrey has been released on bond.

Monge was reported missing April 1 after leaving a Denver nightclub. Police found her body in Weld County on Sept. 7, buried under a cottonwood tree near Keenesburg, about 40 miles from Denver.

9Wants to Know learned Forbes physically took investigators to the crime scene on Sept. 7 and showed them the exact spot where Monge was buried, near Interstate 76 and Weld County Road 53.

In exchange for his guilty plea, Forbes avoided the death penalty.

In a separate case, Forbes also reportedly pleaded guilty to trying to murder a woman and setting her townhome on fire in July in Fort Collins. He will serve a 48-year sentence for that case after his life sentence for Monge's murder.